Okay this is the update after taking a sample of the tanks water to wild on pets at Greenstone. As it turns out the hydrometer was 100% correct and salinity levels off the chart with their own independant reading as well. Their advise is to take out a liter in the morning and replace it with RO and last thing at night the same thing, thus replacing 2 liters per day until it is right. Sounds like excellent advise and also more or less the advise given here on this forum. Thanks to all of you who have tried to help, your advice was phenominal and of great value to us.
Salinity
- Thread starter Daphne Annandale
- Start date
This is what is most likely the scenario.
The basics of testing Specific Gravity with a Hydrometer.
1) Ascertain what the hydrometer is indicating. Some Hydrometers indicate Density, but most Specific gravity.There is a difference.
2) Ascertain the calibration temperature of the hydrometer. The temperature of the water must be tested at the hydrometer calibration temperature.
The following scenario is common.
A standard Hydrometer is used that is calibrated at 60/60f 15.56c
The aquariust is advised to make up the water to a Specific Gravity of 1.026 and NO reference temperature is advised. A Specific gravity of 1.026 at 15.56c is a SALINITY 33.7
The aquariust is advised to make up the water to a Specific Gravity of 1.026 and NO reference temperature is advised. A Specific gravity of 1.026 at 20c is a SALINITY 35.1
The aquariust is advised to make up the water to a Specific Gravity of 1.026 and NO reference temperature is advised. A Specific gravity of 1.026 at 25c is a SALINITY 36.8
Water that is at room temperature (20c) is made up to a SG of 1.026. on a 15.56 calibrated Hydrometer. Because the temperature of the sample water is 20c this equates to a corrected SG of 1.0269 at 15.56c This is a Salinity of 36.4
Water is added to a tank that is at 25c and the SG on the Hydrometer now reads 1.024. This is a salinity of 33.8 So guess what happens. Correct the aquariust lifts the SG to read 1,026 on the 15.56c Hydrometer increasing the Salinity to 39.4
Now the temperature of the tank increases during the day to 28c and the SG is tested on the Hydrometer and the SG now reads 1.0245. This is a Salinity of 39.4 So you guessed it the aquariust adds more salt to increase the SG to 1.026 on his 15.56 calibrated hydrometer increasing increasing to a Salinity 42
When the water is next checked at say 24c
Specific gravity toooo high.
So how does this help you?
You must check the water when it is at the calibration temperature of the Hydrometer. This will stop conflicting readings and you trashing your tank.
I will send @viper357 a calculator to put up that will correct SG readings on hydrometers and Refractometers that are not ATC. this will allow one to measure the SG at any temp and get a corrected SG.
The basics of testing Specific Gravity with a Hydrometer.
1) Ascertain what the hydrometer is indicating. Some Hydrometers indicate Density, but most Specific gravity.There is a difference.
2) Ascertain the calibration temperature of the hydrometer. The temperature of the water must be tested at the hydrometer calibration temperature.
The following scenario is common.
A standard Hydrometer is used that is calibrated at 60/60f 15.56c
The aquariust is advised to make up the water to a Specific Gravity of 1.026 and NO reference temperature is advised. A Specific gravity of 1.026 at 15.56c is a SALINITY 33.7
The aquariust is advised to make up the water to a Specific Gravity of 1.026 and NO reference temperature is advised. A Specific gravity of 1.026 at 20c is a SALINITY 35.1
The aquariust is advised to make up the water to a Specific Gravity of 1.026 and NO reference temperature is advised. A Specific gravity of 1.026 at 25c is a SALINITY 36.8
Water that is at room temperature (20c) is made up to a SG of 1.026. on a 15.56 calibrated Hydrometer. Because the temperature of the sample water is 20c this equates to a corrected SG of 1.0269 at 15.56c This is a Salinity of 36.4
Water is added to a tank that is at 25c and the SG on the Hydrometer now reads 1.024. This is a salinity of 33.8 So guess what happens. Correct the aquariust lifts the SG to read 1,026 on the 15.56c Hydrometer increasing the Salinity to 39.4
Now the temperature of the tank increases during the day to 28c and the SG is tested on the Hydrometer and the SG now reads 1.0245. This is a Salinity of 39.4 So you guessed it the aquariust adds more salt to increase the SG to 1.026 on his 15.56 calibrated hydrometer increasing increasing to a Salinity 42
When the water is next checked at say 24c
Specific gravity toooo high.So how does this help you?
You must check the water when it is at the calibration temperature of the Hydrometer. This will stop conflicting readings and you trashing your tank.
I will send @viper357 a calculator to put up that will correct SG readings on hydrometers and Refractometers that are not ATC. this will allow one to measure the SG at any temp and get a corrected SG.
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viper357
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That's probably what happened, it's an easy to make mistake, I know I've done it before, until I learned to label my drums.
Whenever you do a water change, make sure you test the salinity of the water before you add it to the tank, it is absolutely vital that you do this, and get the new water up to temperature as well before you test it and add it to the tank, about 25/26 Celsius roughly.Will do that Viper, thanks alot. We have labelled the drums but obviously was told that the one container was RO and the other Sea, but also tried to taste it to make sure and tasted like RO. This i think is what happened. By adding 2 litre a day and taking 2 l out we should get down within 3 days or so???
That's probably what happened, it's an easy to make mistake, I know I've done it before, until I learned to label my drums.
100% if the calibration temp on the hydrometer is 25c. If the calibration temperature on the hydrometer is 15.56 then you will be mixing to a very high Salinity.
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It may take longer than this if you do 2litres a day but it is 100% safe and good advice. There is no rush to drop your salinity, although you could likely do 5 litres a day with no issues (split out over the day of course)
I often add 25l of RO water (to replace evaporation loss) at one time on an approximate 400l water and have had no issues whatsoever = about 6l /100litres